Liquid level indicator



Filed April 6, 1934 2 Sheets-Sheet 1 INVENTOR.

Nov. 19, 1935. K. E. STUART.

LIQUID LEVEL INDICATOR Filed April 6, 1954 2 Sheets-Sheet 2 A 1 w ,1 x

I N V EN TOR.

Patented Nov. 19, 1935 UNITED STATES PATENT OFFICE I LIQUID LEVELINDICATOR Application April 6, 1934, Serial No. 719,346

2 Claims.

My invention relates to means for indicating liquid levels in closedpressure tanks and more particularly tanks containing volatile liquidsof a corrosive or noxious nature, such as liquid chlorine.

In the manufacture and liquefaction of chlorine, also in the plants oflarge consumers of chlorine, it is necessary or desirable to providechlorine storage containers. These containers may hold as much as thirtytons of chlorine, with the liquid standing at about two-thirds of theheight, the remaining space being, of course, filled with chlorine ingas phase. Owing to the hazard involved in case of a leak permittingsuch a quantity of chlorine to suddenly escape, it is consideredinadvisable to provide connections below the liquid level through whichthe usual sight glass could be connected. Hence such storage tanks haveheretofore been without any means for indicating the level of the liquidcontents. When drawing off chlorine the liquid boils more or less andthe cooling effect produced is often sufficient to indicate the liquidlevel by a frost line on the outside of the tank. However, this is notthe case if the tank is covered with heat insulation; moreover, when thechlorine is not drawn upon regularly the frost line disappears.

In plants of the character referred to, the quantity of chlorine on handhas therefore at times been somewhat uncertain and the possibility of ashortage has occasionally been an awkward op erating factor. The objectof my invention is to remedy this state of affairs by providing asimple, dependable liquid level indicator meeting all the conditions ofservice and introducing no new hazards in the industries having to dowith chlorine.

Referring to the drawings:

Fig. 1 is a sectional elevation of. portion of a chlorine storage tankequipped with my invention.

Fig. 2 is a cross-sectional elevation of the same along line a-a of Fig.1.

Fig. 3 is an enlarged detail, in section, of the sight glass andindicator rod.

Fig. 4 is an enlarged view showing the indicator scale.

Fig. 5 is a cross section through the line b-b of Fig. 4.

In the figures, I is the shell of the storage tank which is of circularsection, placed horizontally and provided with the usual dished end 2. 3is an opening in the top of shell I which may be provided with pipeconnection 4, flanged at 5. 6 is a pipe inserted through opening 3 andflanged at I by means of which flange a pressure tight joint with flange5 is made. Pipe 6 extends about half way into tank I and its lower endis provided with yoke 8 to which lever I0 is pivoted at point 9. At oneend, lever Ill carries float I l and at the other end counterbalanceweight l2. At point l3, beneath the lower end of pipe 6, the link I4 ispiv- 5 oted to lever ID. The lower end of link I4 supports indicator rod15. The upper end of rod l5 projects into sight glass l6. Sight glass i6consists of a heavy walled tube, preferably closed at its top end, andinserted through stufling box It. 10 Stuffing box I! which is providedwith packing chamber l8, screws into coupling I9 upon the upper end ofpipe 6. The stuffing box giand 2c is pressed down to compress thepacking of the stufllng box by the member 2|, which screws over stuflingbox I! and is locked by nut 22. The member 2| carries welded to it atits upper side the tubular guard 23 in which sight glass I6 is encased.The space between sight glass l6 and guard 23 is filled with plasticmaterial, so that the sight glass :0 is reenforced against bursting byguard 23. The guard 23 is slotted at opposite sides to permit visionthrough the sight glass. The upper end of, indicator rod I5 maytherefore be seen through the sight glass.

The float I l is heavy walled to resist collapsing pressure, and as thiswould render it too heavy to perform its function properly, thecounter-weight I2 is applied in order to give the float the necessarybuoyancy.

The distance between points 9 and l 3 bears such a relation to thedistance from point 9 to float H and travel of float II, that the entiretravel of indicator rod may be seen through sight glass "5.

In the lower part of stufling box I1 is formed a 35 chamber 24, of adiameter suflicient to provide clearance for sight glass l6 and of alength corresponding to that of the chamber l8, so that as gland 20 ispressed down by nut 2|, guard 23 may force sight glass l6 down with itinto chamber 24. 40 Indicator rod i5 enters chamber 24 through aclearance hole, 1. e., a hole of such diameter that the clearance isjust suflicient to permit rod I5 to slide freely through it. If theentire sight glass should be broken off, together with its guard 23, 45the leakage around indicator rod l5 would therefore be only that whichcould flnd its way through a minor clearance. If. preferred, chamber 24may likewise be provided with packing to form a stuffing box aroundindicator rod l5, sight glass It in 50 this case serving as a gland. Ifpacking is used I in chamber 24 it should be less tightly packed thanthat in stufllng chamber l8, so that leak-proof pressure may be appliedto sight glass IS without creating too much friction upon indicator rodI5. 55

As a further precaution in case the sight glass it should crack or beknocked oli, soap 2!} is provided which may be screwed down upon nut 2iin such a way as to completely enclose the sight glass and guard.

The moving parts oi this device should be oi some metal that isresistant to chlorine. Steel is sufdciently resistant to drychlorineforthe heavier parts-but part #3 should? be of analloy of copper and nickeland indicator rod 25 'of'a similar alloy, or silver, so that no bindingcan.

rosion.

Although a pressure storage tank may obviously be placed on end, it ismore usual'to place'j large tanks as indicated on the drawings. Whenthus placed the cross-sectional area is not proportional to incrementsof height, and therelationship is further complicated by the dishedhead. The scale to show equal increments of volume will therefore beirregular and quite special, the graduations being closer near themiddie of the scale and further apart at its two extremities. Such ascale is illustrated in Fig. 4 and may be calculated for a given storagetank or determined experimentally by forcing into the tank equalincrements of liquid, say one ton of chlorine, and marking the positionof the indicator rod upon the scale.

Although I have described my invention a applied to a storage containerfor chlorine, I do not wish to be limited thereto, as my liquid levelindicator is obviously applicable to any pressure tank and especiallyuseful with all corrosive, noxious or toxic liquids.

What I claim is:

-1. A device for indicating liquid levels in pres sure-tight containerscomprising a float adapted to be supported by the liquid, an indicatorrod supported by said float and projecting outwardly of said containerthrough a stufing-box into a. tubular, pressure-tight sight glass,packing in said stufing box bearing against said rod, the inner end ofsaid sight glass bearing against said packing, a slotted guard memberenclosing said ight glass and bearing against' the outer end thereof andmeans for bringing sealing pressure g against said rod through saidpacking, said sight take place at opening 25 through even slight cor'glass and said guard member.

2. A device for indicating liquid levels in pressure-tight containerscomprising a fioat adapted to be supported by the liquid, an indicatorrod supported by said float and projecting outwardly through an innerstufiing cox into a tubular pressure-tight sight glass, packing in saidstuffing box bearing against said rod, the inner end of said sight glassbearing against said packing, an outer stufing' box surrounding theinnerpor tion of said-sight glass, packing in said outer striding-boxbearing against said sight glass, the packing'i'n said 'outer stuiiingbox being more densely compressed than the packing in said'imner'stuflingbox, a'slotted guard member enclosing said sight glass andbearing against the outer end thereof and means for" bringing,relatively light sealing pressure against said rod through the packingin said inner stuflingvbox, vsaid-sight glass and said guard member andfor simultaneouslybringing relatively heavy sealing pressure againstsaid'sight, glass through the packs ing in said outer stufiing box andsaid guard member. 1

STUART:

